Should obesity be recognised as a disease?

Yes—John P H Wilding and Vicki Mooney

Excess accumulation of body fat (obesity) develops because of abnormal biological regulation of energy balance, has multiple complications, and should be considered a disease. The Oxford Dictionary defines disease as “a disorder of structure or function . . . especially one that produces specific symptoms . . . and is not simply a direct result of physical injury.”1 Obesity, in which excess body fat has accumulated to such an extent that health may be adversely affected, meets that definition, and the World Health Organization has considered it a disease since 1936.2

Obesity has rapidly increased in prevalence and now affects 29% of the population in England.3 Metabolic complications include type 2 diabetes, fatty liver disease, and hormone dependent cancers; mechanical complications of joint pain, arthritis, increased obstetric risk, and sleep apnoea are common, and obesity may adversely affect mental health, partly because of stigmatisation.3 Genetic and environmental factors contribute to its aetiology and influence the underlying biology of weight regulation, the sites of fat storage, and the risk of complications.4